RRB NTPC CBT-1 previous year question
The arithmetic mean of 10 observations is 42. Three of the observations are 30, 38, and 50. The remaining six observations have an average of 45. Find the missing observation.
Asked in RRB NTPC 2026 — 16 June Shift 1 · Quantitative Aptitude
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Correct answer: (C) 32
Total of 10 observations = 10×42=420. The three given observations sum to 30+38+50=118, and the six with average 45 sum to 270. Together these 9 observations total 388, so the missing 10th observation = 420-388 = 32.
हिंदी में प्रश्न
10 प्रेक्षणों का समांतर माध्य 42 है। इनमें से तीन प्रेक्षणों का मान 30, 38 और 50 है। शेष छह प्रेक्षणों का औसत 45 Sl अज्ञात WATT ज्ञात कीजिए।
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उत्तर और व्याख्या देखें
सही उत्तर: (C) 31
10 प्रेक्षणों का कुल योग = 10×42=420। दिए गए तीन प्रेक्षणों का योग 30+38+50=118 है, और औसत 45 वाले छह का योग 270 है। साथ में इन 9 प्रेक्षणों का योग 388 है, अतः लुप्त 10वाँ प्रेक्षण = 420-388 = 32 है।
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